For the early part of the second day it looked as if Cooper and Borthwick may fade away after a poor start to the better-ball round at King’s Lynn.
At the eighth hole Borthwick, who has a handicap index of 19.1, recorded a gross birdie for the first of his three four-point hauls and the comeback was on.
But he reserved his best for the closing two holes as the tournament came to a thrilling climax. Borthwick made a second gross birdie on the par-4 17th hole and then closed out with a rock-solid par down the last.
It meant that on those two closing holes alone he and Cooper recorded seven points – good enough to lift them clear at the summit.
Cooper said: “Gary played the last two holes incredibly – he hit some really good shots. He had an outstanding finish.
“He’s just very steady, down the middle, doesn’t really get into too much trouble and his putter on the second day was red hot. He probably holed four or five very, very good putts.
“It was a brilliant couple of days. I class myself as a steady golfer and we just dovetailed well. Foursomes is always a tough format but we both played and hit the ball a lot better than we did on the second day. Better-ball you just have to grind it out and keep the score going. It’s been fantastic.”